Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already establish a safe read-only, non-destructive, closed-world operation. The description adds useful context about the reading's content and desired plain-language style, but says nothing about optional birth time/gender effects, input assumptions, or output structure.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The purpose is front-loaded in the first clause, followed by example use cases and a short response-style instruction. Every sentence is functional and there is no filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a read-only compatibility tool with no output schema, the description gives an adequate picture of what the reading covers and how to phrase it. However, with six parameters and no schema descriptions, it omits enough parameter detail that an agent may not know how to use birth time and gender correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must carry parameter meaning. It only refers to 'birth dates' and does not explain the optional birth times, gender parameters, or expected date formats, leaving half the parameters without semantic guidance.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific relationship-compatibility reading from two birth dates, with the dimensions covered (ease, friction, mutual contributions). This is clearly distinct from sibling tools about birth time or a year ahead, so an agent can select it without inspecting the schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives concrete example question types ('Are we compatible?', relationship, marriage, partner questions), which clearly signals when to use it. It does not name alternatives or state when not to use it, so it stops short of explicit routing guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.